io.jooby.Value to method should be marked as nullable

[agentgt]

in io.jooby.Value

We have

@Nonnull <T> T to(@Nonnull Class<T> type);

It should be

@Nullable <T> T to(@Nonnull Class<T> type);

This is because in Context we have:

  @Nullable <T> T convert(@Nonnull ValueNode value, @Nonnull Class<T> type);

I'm surprised the null checking didn't pick this up or maybe it isn't turned on for this project.

[agentgt]

Whoops it looks like I got it backwards. convert should be marked @Nonnull on its return value.

  @Override default @Nullable <T> T convert(ValueNode value, Class<T> type) {
    T result = ValueConverters.convert(value, type, getRouter());
    if (result == null) {
      throw new TypeMismatchException(value.name(), type);
    }
    return result;
  }

Anyway the reason I found this out is trying to handle blank query parameters. For example: ?id=&stuff=. Both id and stuff are not a MissingValue but a SingleValue (which I expect) and if you convert it to anything but a String you will get a typemismatch.

This is happening because some of ourJavascript developers are assuming empty parameters will be null.